Ignition of gas burners



Sept. 13, 1966 HUGHES L 3,272,254

IGNITION OF GAS BURNERS Filed May 20, 1964 5 Sheets-Sheet 1 Fvanvc 1 s Hughes 4- STan lay W1 111m B y flwmwkw S p 1966 F. HUGHES ETAL IGNITION OF GAS BURNERS 3 Sheets-Sheet 2 Filed May 20, 1964 y%ls Hugke STanley W lh mS Sept. 13, 1966 Filed May 20, 1964 F. HUGHES ETAL 3,272,254

IGNITION OF GAS BURNERS 5 Sheets-Sheet 5 Francis Hughe ks7zinl fg iLlllh I United States Patent 3,272,254 IGNITION 0F GAS BURNERS Francis Hughes, Leamington Spa, and Stanley Ralph Williams, Oxfordshire, England, assignors to Sidney Flavel 8: Company Limited, Leamington Spa, England, a British company Filed May 20, 1964, Ser. No. 368,930 Claims priority, application Great Britain, Oct. 3, 1963 38,9 10/ 63 4 Claims. (Cl. 158-125) This invention relates .to the ignition of gas burners by igniters in which an igniter flame is lit by an electric filament. It is especially suitable for domestic appliances but is also applicable to burners for industrial use.

In the known devices the turning on of a main gas tap admits gas to the igniter, and it is then arranged that the circuit of the electric filament is closed either manually or by some mechanically or thermally operated device which lights the igniter flame. To avoid damage to the igniter filament, the gas supply to the igniter and the electric supply to the rfilament is cut off automatically after release of the manual control, or after a pre-determined time delay.

In practice, it is diflicult to ensure reliable operation because when the equipment has not been used for a time, possibly even for only a matter of hours, air diffuses into the supply pipe between the gas tap and the igniter burner and an ignitable gas mixture may still not have reached the igniter burner by the time the delay device switches it off, or the consumer has released the manual control. It is an aim of the invention to overcome this difliculty.

The present invention consists in a gas-fired appliance including a device for the ignition of a main gas burner of the appliance of the kind having an igniter in which an igniter flame is lit by an electric filament, wherein the gas supply to the igniter is fed through a thermally controlled valve actuated by a bi-metallic strip or similar thermally responsive element which is heated by a flame lit by the igniter the arrangement being such that the igniter is extinguised and its filament switched off only when that flame is alight.

The control of the igniter is thus no longer dependent on time, or consumer operation beyond that of initially turning on the gas; instead, it remains in operation until the flame acts to disconnect it, and thus ignition is ensured, irrespective of any delay there might be in an ignitable mixture reaching the igniter burner.

The electrical part of the igniter is preferably controlled by a diaphragm switch or equivalent pressure-sensitive switch in the gas supply to the igniter so that closure of the thermally-controlled valve by the thermally responsive element in addition to stopping the gas supply to the igniter also cuts off the electric current to the filament.

The flame lit by the igniter may be that of a pilot jet connected in the pilot gas supply upstream of the thermally-controlled valve. This pilot remains alight after the igniter has been switched ofl, and it keeps the thermally responsive element hot thereby keeping the valve closed and the igniter out of action.

The pilot flame thus ignited may be used to ignite a main burner which may be directly connected to the supply or through a protective flame failure device, for example in which the pilot flame already mentioned or an auxiliary pilot flame heats a bi-metallic strip to open a main gas valve controlling the main burner.

Igniter control according to the invention is also suitable for inclusion with a time controlled valve for allowing the main burner to be ignited at a pre-set time. When the time controlled valve is in circuit, at the pre-set time it admits gas to an auxiliary pilot which is lit by a primary pilot. The auxiliary pilot heats a bi-metallic or similar element not exposed to the primary pilot flame and which opens the valve supplying the main burner or burners. The primary pilot and igniter may be arranged to be actuated either on operation of the time-controlled valve or on operation of a main gas tap when the timecontrolled valve is set and put in circuit.

The thermally controlled valve for extinguishing the igniter and the protective flame failure device may be combined in a single valve under the control of a single thermo-responsive element.

Embodiments of the invention will now be descri-bed by way of example with reference to the accompanying drawings in which,

FIGURE 1 shows diagrammatically an ignition device for lighting a pilot flame.

FIGURE 2 shows diagrammatically the ignition device illustrated in FIGURE 1 and a main burner valve incorporating a flame failure device, and also indicating schematically a time control switch operating the main valve.

FIGURE 3 is a side view of a double-acting valve combining an ignition device according to the present invention and a main burner valve.

IFIGURE 4 is a vertical section through the valve shown in FIGURE 3.

FIGURE 5 is a perspective view of a cooker partly broken away to show the double-acting valve shown in FIGURES 3 and 4 installed in the cooker.

Referring to the ignition device shown in FIGURE 1, an igniter 5 having an electric filament, not shown, is supplied with gas fed through a thermally controlled valve 6. The electric filament is electrically connected to a battery 7 through a diaphragm switch 8 which is included in the gas supply from the valve 6 to the igniter 5. Gas is supplied to the valve 6 from a main supply pipe 9 to a main burner 10 to be ignited by the device, the gas for the valve 6 being taken from the supply pipe 9 downstream of a tap 11 controlling the main gas supply. The thermally controlled valve 6 is actuated by a bimetallic strip 12 arranged to be heated by the flame of a pilot burner 13 supplied with gas upstream of the valve 6. The igniter is arranged so that its flame is directed towards the pilot burner 13.

When the tap 11 is initially turned on gas passes through the valve 6 to the igniter and its pressure actuates the diaphragm switch 8 so as to close the circuit to the filament in the igniter to energize it and hence light the igniter flame. The igniter flame ignites gas issuing from the pilot burner 13 to produce a pilot flame which impinges on the bi-metallic strip 12 of the valve 6 causing the valve to be closed, shutting oil the gas supply to the igniter so that the igniter flame is extinguished. As soon as the gas supply is cut otf the diaphragm switch breaks the circuit to the filament. Since the pilot burner is supplied with gas upstream of the valve 6 the pilot flame remains alight and continues to impinge upon the bimetallic strip keeping it hot so that the valve 6 is maintained in its closed condition and the igniter cut off. Failure of the gas supply to the pilot burner cannot cause operation of the igniter because the pilot burner and igniter are fed from the same supply.

In practice lighting a burner provided with an ignition device as shown is very simple. The user merely has to turn on the main gas tap 11 and all the remaining operations are automatic. There is no danger, as in some known devices, that the user will have to turn off and try again as the igniter of the present arrangement will remain in operation until ignition has taken place.

The main burner 10 could be supplied with gas, under manual control alone, directly from the main tap 11, but

is preferably under the protection of a flame failure device, for example as described later in the modification of FIGURE 2 without time control.

In FIGURE 2 the ignition system of FIGURE 1 is shown in conjunction with a main gas valve 14 of a flame failure device controlling a main burner 24. The main gas valve 14 is positioned close to the igniter and thermally controlled valve 6. Incorporated in the housing of the main valve 14 is an auxiliary burner 15 whose nozzle 16 is so directed that when gas is supplied to the auxiliary burner and issues from the nozzle 16 it will be ignited by the pilot flame. The flame ignited at the auxiliary burner nozzle 16 plays on a bi-metallic strip 17 which when heated opens the main valve 14 to permit gas to pass to the main burner 24.

Gas is supplied to an innlet 18 of the main valve 14 by a main gas supply pipe 19 under the control of a gas tap 20. Between the tap 2i) and main valve a secondary supply pipe 21 is connected to the main supply pipe and takes gas to the thermally cont-rolled valve 6. From this secondary supply pipe 21 gas is also taken to the auxiliary burner 15. The gas supply from the secondary supply pipe 21 to the auxiliary burner 15 may be taken directly to the auxiliary burner or, as shown in FIGURE 2, it may first have to pass through a time controlled valve 22 so that the gas reaches the auxiliary burner and hence the main burner at a pre-set time. With this latter arrangement the user turns on the gas tap permitting gas to pass to the thermally controlled valve 6 and igniter to ignite the pilot flame, which operates the valve 6 thereby extinguishing the igniter in the manner previously described, but the supply to the auxiliary burner remains cut off so that the main valve cannot be opened until a time pre-set by the user, when the time controlled valve 22 opens. As soon as the time controlled valve 22 opens gas passes to the auxiliary burner to be ignited by the pilot flame and heat the bi-metallic strip 17 causing it to open the main valve so that gas from the main supply pipe 19 can pass through the valve to an outlet 23 which delivers gas to the main burner 24. A selector switch 25 is provided in the supply from the secondary supply pipe to the auxiliary burner so that the user can arrange for the gas to be supplied either directly to the auxiliary burner or by way of the time controlled valve 22, as required. The time controlled valve 22 is arranged so that it controls both the supplying and cutting off of the gas to the main burner.

In the event of the gas supply failing both the pilot an auxiliary flames will of coursebe extinguished and since the bi-metallic strip 17 is no longer being heated it will cause the main valve to close. If the used is unaware of the gas failure and the gas tap 20 has not been turned off, when the gas supply is returned the pilot flame will automatically be ignited again and if the time-controlled valve is still open the main burner will be re-lit so that there is no danger of gas escaping.

If a time-controlled valve is not provided gas may be supplied directly to the auxiliary burner and igniter system in the way indicated by the chain-dotted line 63 in FIGURE 2.

The thermally-controlled valve 6 and main valve of FIGURE 2, may be combined in a double-acting valve as shown in FIGURES 3 and 4. The valve is controlled by a single bi-metallic strip 26 which is actuated by a singel pilot burner 27. An igniter 28 and diaphragm switch 29 actuating ,the igniter filament are also mounted on the body 30 of the valve. As shown in FIGURE 4, a bore 31 is formed through the body 30 of the valve, into one end of which bore, the lower end as viewed in FIG- URE 4, is screwed a closure member 32 to close that end and into the other, upper end is fitted a sleeve 33 having an external diameter complementary to the bore 31. The interior of the sleeve 33 is separated into upper and lower portion 34 and 35 respectively by a dividing wall 36 across the bQ t Of the sleeve. The exterior of the lower end of the sleeve is screw-threaded and engages an internal screw thread in the bore 31. The upper end of the sleeve is closed by a screw cap 37 screwed int-o the end of the upper portion 34 of the sleeve interior. Extending co-axially through the sleeve is a valve spindle 38, a hole 39 in which the spindle 38 is a free sliding fit being provided in the dividing wall 36 for the spindle to pass through. The upper end of the spindle projects through and beyond the screw cap 37. The lower end of the spindle loosely engages a socket 40 in a valve head 41 which is arranged to operate in the bore 31 between the lower end of the sleeve and the closure member 32, and which has oppositely directed annular face-s 42 and 43 for engaging respectively a seating 44 formed by the lower end of the sleeve and a seating 45 formed on the inner end of the closure member. The valve head 41 is urged upwards by a helical compression valve spring 62 so that its upper annular face 42 normally engages the seating 44 at the lower end of the sleeve, as shown in FIGURE 4. Inside the upper portion 34 of the sleeve 33 a sealing collar 46, fitting closely but slidably on the spindle is urged against the dividing wall 36 by a helical compression spring 47 around the spindle so as to prevent gas which may seep through the clearance hole 39 entering the upper portion of the sleeve. Secured to the spindle in the lower portion 35 of the sleeve is a collar 48, and fitted around the spindle between the collar 48 and the plunger 41 is a small compression spring 49 which bears at its ends against the collar 48 and head 41. This spring 49 normally urges the spindle upward-s. But in FIG. 4 the spring 49 is shown in its fully extended relaxed condition.

The bi-metallic strip 26 is of U-shape and is secured by its one limb 50 to the screw cap 37 and its other limb 51 overlies the projecting upper end of the spindle.

The diaphragm switch as shown in FIGURE 3, is supported on the valve body by screwing its gas inlet 60 directly into the end of the passage 59. The igniter which is positioned close to the pilot burner is mounted by a short gas supply pipe 61 connected toand supported by the diaphragm switch.

A second gas outlet 53 opening through the valve body communicates with an outlet port 54 through the wall of the lower portion 35 of the sleeve.

The double-acting valve as just described with reference to FIGURES 3 and 4 of the accompanying drawings is shown in FIGURE 5 installed ina cooker for controlling the gas supply to a burner 64 for heating an oven 65 of the cooker. The cooker has a casing 66 enclosing the oven 65 and a hotplate 67, having burners 68, in the upper surface of the casing 66 above the oven 65. The front of the oven is closed by a bottom-hinged drop-down door 69. The valve is disposed below the level of the oven floor 70 close to the burner 64 which is arranged in an opening 71 in the floor 70. The main inlet 52 of the valve is connected to a main gas supply pipe 72 and the second outlet 53 is connected by a pipe 73 to the burner 64. Gas supply to the hotplate burners 68 is controlled by taps 74 and to the oven burner 64, through the valve, by a tap 75; the taps 74 and 75 being on a control panel 76 included in the casing 66 in front of the hotplate 67. If required the valve may be connected to the gas supply through a time-controlled valve.

When the gas supply is turned on gas enters the valve by way of the main inlet 52 but is prevented from reaching the main outlet 53 because as stated, the head 41 is normally urged against the seating 44, so that the gas cannot enter the lower portion 35 of the sleeve and pass to the second outlet through the outlet port 54. The first outlet passage is open, however, so that gas can pass through the diaphragm switch to the igniter, the igniter filament being energised as before by the diaphragm switch when gas passes through it to light the igniter flame. As soon as the igniter flame is lit it in turn lights the pilot burner flame. The pilot burner is so positioned that its flame plays on and heats the bi-metallic strip. On being heated the bi-metallic strip 26 deflects causing its limb 51 which overlies the spindle to move downwards and push the spindle 30 downwards so that through the small compression spring 49 the head 41 is also moved downwards, against the action of the valve spring 62 away from the seating 44. Once the head 41 has moved away from the seating 44 gas can pass into the lower portion of the sleeve and through the outlet port 54 to the second outlet 53 and hence to the oven burner 64. The valve head 41 is moved downwards until it seats on the seating 45 and shuts off the second outlet passage 56. Thus gas can no longer pass to the igniter flame and it is extinguished and since no gas is passing through the diaphragm switch to actuate it, it cuts oil the current to the igniter filament as before. Even though the valve head has moved to close the second outlet passage 59 the first outlet 55 remains open so that gas continues to pass to the pilot burner 27 and the pilot flame remains alight to keep the bi-rnetallic strip deflected. The valve remains in this condition until the gas tap 75 controlling the gas supply to the oven burner 64 is shut otf to stop the gas supply or the gas supply fails, when, since the pilot flame is extinguished and the bi-metallic strip no longer heated, the valve spring 62 returns the head 41 to its normal position.

We claim:

1. A gas-fired appliance incorporating means for controlling the lighting of a main burner comprising a single pilot burner, means for supplying gas to said pilot burner directly from a main supply, an igniter burner incorporating an electrically heated igniter filament, means for supplying gas to said igniter burner including a valve con trolled by thermally responsive means influenced by the flame of the pilot burner, and means for controlling the electrical circuit of said igniter filament comprising a pressure-sensitive switch in a pipe line between said valve and said igniter burner, said switch breaking the circuit to said filament when the gas supply to the igniter burner is cut oil by the closing of said valve by the thermally responsive means heated by the flame of the pilot burner.

2. A gas-fired appliance as in claim 1 further incorporating a flame failure device comprising a second pilot burner adjacent to the first, a valve controlling the supply of gas to the main burner, and a second thermally responsive device controlling said valve and influence by said second pilot burner.

3. A gas-fired apppliance incorporating means for controlling a main burner comprising a valve body, an inlet to said body adapted .to be connected to a gas supply, a first outlet from said body adapted to be connected to the main burner, a pilot burner, a second outlet leading to said pilot burner and in communication at all times with said inlet, an igniter for said pilot burner incorporating an electric filament, a pressure sensitive device through which gas and electric current are supplied to said igniter, a thermally responsive device influenced by the flame of said pilot burner, and a double-acting valve member movable by said thermally responsive device from a normal position in which it closes communication between said inlet and said first outlet and maintains open communication between said inlet and said third outlet and a position in which it opens communication between said inlet and said first outlet and closes communication between said inlet and said third outlet.

4. A control device for a main burner of a gas-fired appliance comprising a body, a bore in said body, a gas inlet to said bore, a first gas outlet from said bore spaced axially from said inlet and adapted to supply gas to said main burner, a first valve seat between said inlet and said first outlet, a pilot burner, a second outlet from said bore leading to said pilot burner, said second outlet being at all times in communication with said inlet, a pressure sensitive switch controlling the circuit of an igniter for said pilot burner, a third outlet from said bore leading to said pressure sensitive switch, a second valve seat between said inlet and said third outlet, a double-ended valve member adapted for alternative engagement with said first and second valve seats, spring means normally urging said valve member into engagement with said first seat to cut otf communication between the inlet and said first outlet and allow gas to pass to said third outlet, an axially movable rod cooperating with said valve member, and thermally responsive means influenced by the flame of said pilot burner and acting on said rod for moving said valve member out of engagement with said first valve seat and into engagement with said second valve seat to allow gas to pass from the inlet to said first outlet and to cut oflf said third outlet from the inlet.

References Cited by the Examiner UNITED STATES PATENTS 2,315,959 4/1943 Horstmann 158-126 2,371,020 3/1945 Beam 158-125 X 2,564,869 8/1951 Weber 158-l26 X 2,625,216 1/1953 Strobel 158-126 X FOREIGN PATENTS 1,082,206 5/ 1960 Germany.

FREDERICK KETTERER, Primary Examiner. 

1. A GAS-FIRED APPLIANCE INCORPORATING MEANS FOR CONTROLLING THE LIGHTING OF A MAIN BURNER COMPRISING A SINGLE PILOT BURNER, MEANS FOR SUPPLYING GAS TO SAID PILOT BURNER DIRECTLY FROM A MAIN SUPPLY, AN IGNITER BURNER INCORPORATING AN ELECTRICALLY HEATED IGNITER FILAMENT, MEANS FOR SUPPLYING GAS TO SAID IGNITER BURNER INCLUDING A VALVE CONTROLLED BY THERMALLY RESPONSIVE MEANS INFLUENCED BY THE FLAME OF THE PILOT BURNER, AND MEANS FOR CONTROLLING THE ELECTRICAL CIRCUIT OF SAID IGNITER FILAMENT COMPRISING A PRESSURE-SENSITIVE SWITCH IN A PIPE LINE BETWEEN SAID VALVE AND SAID IGNITER BURNER, SAID SWITCH BREAKING THE CIRCUIT TO SAID FILAMENT WHEN THE GAS SUPPLY TO THE IGNITER BURNER 